cross bows trigger mechanisms

T

trapper

Active User
Registered
Joined
Nov 17, 2012
Messages
46
At laste I'm back in my shop and getting on with some new projects. I'm building a pelicating machine based on old terrcoduplicator parts to make gunstocks and the like. I'm starting making a crossbow based upon a BSA MK6 (styled ) stock. te intention is this will be running at about 100lbs pull. the prod is being made in fibreglass/carbon fibre.
Im lost for any dimensioned plans for a trigger mechanism has anyone any guidance they can give?
 
Why not use the AR's fire control group? Timney makes a triggers makes a self-contained upgraded trigger unit that just drops in place. It would need only two pin holes for the hammer and trigger pins and the specs for locating those holes are already all over the web. The only other dimensions you would need to account for are the pocket to clear the body of the trigger and the trigger slot for the booger hook. Using an AR style trigger will also allow you to incorporate an AR safety as well by adding a couple extra holes in the receiver. The hammer that is meant to hit the firing pin could be set up to hit an archery trigger type release.

So what I'm thinking is this put into your receiver...:
http://www.brownells.com/rifle-part...s/ar-15-drop-in-trigger-module-prod40120.aspx

and then the job of actually holding and releasing the bow string done with something like this...:
http://www.ebay.com/bhp/bow-trigger-release

With a cantilever to transfer the AR hammer strike motion to the string release mechanism. If your receiver is thin/short enough, you might be able to do away with the AR parts and just use the bow release mechanism with an extended trigger lever.

That's all I got off the top of my head and is in no way the only way to do this. I've worked on plenty of guns and a few compound and recurve bows, but have about zero actual crossbow experience to go on. I'm not sure how the commercially available crossbows do it (re: the trigger and string hold & release mechanisms) so please take that into consideration before you go buying any parts.:dunno:

EDIT: I just noticed you are located in the UK. I don't think the Timney AR parts will be available to you as they're over $100 (USD) and they are export restricted above that price. You could possible get the standard Mil-spec AR parts in a lower parts kit under that price ceiling and use that if you still wanted to try the AR trigger.

Here's just one of of many of the AR-15 Lower Parts Kits (LPK) available online... (the price is about average from what I've seem of them lately @ around $65 (USD)):
http://www.brownells.com/rifle-part...parts-kit-ar15-sku100011594-55088-115948.aspx

As a bonus, the LPK also has all the safety parts and a pistol grip included if you wanted (or are allowed) to include those parts on your crossbow.
 
GoMopar440 said:
Why not use the AR's fire control group? Timney makes a triggers makes a self-contained upgraded trigger unit that just drops in place. It would need only two pin holes for the hammer and trigger pins and the specs for locating those holes are already all over the web. The only other dimensions you would need to account for are the pocket to clear the body of the trigger and the trigger slot for the booger hook. Using an AR style trigger will also allow you to incorporate an AR safety as well by adding a couple extra holes in the receiver. The hammer that is meant to hit the firing pin could be set up to hit an archery trigger type release.

So what I'm thinking is this put into your receiver...:
http://www.brownells.com/rifle-part...s/ar-15-drop-in-trigger-module-prod40120.aspx

and then the job of actually holding and releasing the bow string done with something like this...:
http://www.ebay.com/bhp/bow-trigger-release

With a cantilever to transfer the AR hammer strike motion to the string release mechanism. If your receiver is thin/short enough, you might be able to do away with the AR parts and just use the bow release mechanism with an extended trigger lever.

That's all I got off the top of my head and is in no way the only way to do this. I've worked on plenty of guns and a few compound and recurve bows, but have about zero actual crossbow experience to go on. I'm not sure how the commercially available crossbows do it (re: the trigger and string hold & release mechanisms) so please take that into consideration before you go buying any parts.:dunno:

EDIT: I just noticed you are located in the UK. I don't think the Timney AR parts will be available to you as they're over $100 (USD) and they are export restricted above that price. You could possible get the standard Mil-spec AR parts in a lower parts kit under that price ceiling and use that if you still wanted to try the AR trigger.

Here's just one of of many of the AR-15 Lower Parts Kits (LPK) available online... (the price is about average from what I've seem of them lately @ around $65 (USD)):
http://www.brownells.com/rifle-part...parts-kit-ar15-sku100011594-55088-115948.aspx

As a bonus, the LPK also has all the safety parts and a pistol grip included if you wanted (or are allowed) to include those parts on your crossbow.
Click to expand...

Thanks for all the info problem as you say is the importing element to the Uk and also the fact that I believe that even to have "firearms parts" for alteration requires a gunsmiths licence here which i dont have . I have a firearms cert for powered air guns etc. Crossbows here dont need any licence at all although you cant hunt birds with them. I can buy a 150lbs crossbow for about £110 ($176) here but as with most things I prefer to make it myself.


My main concern is the safety catch element the knot and tickle sections of the mechanism i can pretty much sort but a more modular approach with safety catch is infinitely more desirable.

Well looks like i'm spending afew evenings at the drawing board here

Thanks again
 
Well it sounds like "plan B" is probably in order then. Just use a bow trigger like I linked in my last post and extend the trigger long enough to reach through the bottom of the crossbow receiver. It would be pretty easy to make a safety that either pushes from the side to block/unblock the trigger (like on most BB guns), or one that would rotate a cam surface to block the trigger (like the AR style of safety). Either way would work so just pick which ever safety style you like best for your application.
 
There are plans for both a wooden and a steel bow crossbow in reprinted copies of "The Boy Mechanic". These were printed back many years ago by Popular Mechanics and re prints can be had today. Search for them on Google. Their triggers have no safety,but you could easily add one as they are simple mechanisms.
 
Google or do a patent search for "crossbow trigger system patent" and you would get so many ideas on different design patents, old and new.
There are many designs that are already expired so it I don't think it would cause legal problems if you copy one of them.
 
You must log in or register to reply here.
Back
Top